In dental treatment, as shown in patent document 1, Japanese Unexamined Patent Application No. 7-136190, because of the easiness of putting on or taking off the denture, various dental attachments utilizing magnetic attractive force have been proposed. A dental attachment 91, which has a magnetic body, is, as shown in FIG. 10, embedded in a denture base 810, which is fixed with an artificial tooth 81. On the side of a tooth root, a keeper 92 made of a soft magnetic material is embedded in a root cap 82 or an implant (the embodiment is abbreviated) is embedded. Therefore the denture, which has the dental attachment 91, can be fixed to the keeper 92 by magnetic attractive force.
As shown FIG. 11 and FIG. 12, in a denture 9 in which are planted a plurality of the artificial teeth 81 in the denture base 810, an artificial tooth 81a corresponding to the place where the dental attachment is embedded and an artificial tooth 81b corresponding to the place where the dental attachment 91 is not embedded, that is not to face the keeper 92, exist.
Until now, after a denture is made, the denture is put in a oral space for about two weeks without the dental attachment (magnetic assembly) built in the denture and when the shrinkage of a gingiva is stabilized, a dentist has combined the dental attachment to the denture. So stress to a gingiva where the dental attachment works is alleviated. But in about half a year, the gingiva gradually shrinks and modification of the denture and recombination of the dental attachment are needed.
On the other hand, dentists desire that the dental attachment should be combined with the denture in the making process before dentists work to put the dental attachment into the denture. However, if the combination is done in the making process, it is unpredictable where and how much gingiva shrinks. Therefore, if the denture, which is combined with the dental attachment in a conventional making process, is put on for about a week, stress to the gingiva is concentrated and a strange feeling or ache is generated.
In more detail, if the denture which is made and completed on the model is used, because the denture is not adequately adapted to the oral space, due to occluding stress, the artificial tooth 81b and the denture base 810 supporting it begin to shrink according to the shape change of the tooth gingiva 88. Meanwhile, the embedded dental attachment 91 cannot shrink because the keeper 92 and dental attachment 91 exist. Therefore, occluding stress is concentrated on the artificial tooth 81a, which is embedded according to the location of the embedded dental attachment 91, and it causes a strange feeling or ache to the patient with the denture 9.
Therefore, especially in the case of combining the dental attachment to the denture in the making process, development of the dental attachment which has a function to alleviate stress to the gingiva has been desired. Also, the development of the manufacturing method of the denture with the dental attachment has been desired.    [patent document 1]: Japanese Unexamined Patent Application Publication No. 7-136190 [patent document 2]: Japanese Unexamined Utility Model Application Publication No. 6-86715